1. Field of the Invention
This invention relates to a scanning printer for printing by scanning on a recorded medium manually, automatically or semi-automatically, and more particularly relates to a scanning printer attachable to and detachable from, as a portable printer, a small-sized and portable external computer.
2. Description of Related Art
Heretofore, a scanning printer connected to an external computer was built in a housing different from the external computer housing and received print data via a cable, for example. A scanning printer that prints while it is scanned manually is proposed in JP-A-48-17630. Because this type of printer prints on recording paper manually, the travel speed is not fixed. Therefore, a displacement detector for detecting relative positional change between a print head and a recorded medium is provided. The change of a relative position caused by the displacement detector moving on the recorded medium is detected and the position of the print head is detected. That is, a roller moved together with the print head touches the recorded medium and is rotated. The change of the relative position between the print head and the recorded medium is detected by detecting the turning angle of the roller.
Because the displacement detector of the printer can detect the change of the relative position between the print head and the recorded medium and because the printer can execute satisfactory printing by controlling the print head in synchronization with the detected change of relative position even if the travel speed is not fixed, a carriage is not required. Further, the printer can be small-sized, with excellent portability, and can be carried and used outdoors. Finally, because printing can be readily executed in an arbitrary position on a recorded medium, printing can be executed on, for example, a bound thick book and document or a paper with large dimensions on which printing cannot be executed using a prior stationary type printer.
However, the prior printer is carried separately from an external computer, making it inconvenient to carry and use outdoors, for example.
In addition, there is a problem in that a procedure for receiving print data from an external computer is required because data sent from the external computer is received by the printer via a cable or by infrared radiation. When the external computer and the printer are connected via a cable, a dedicated cable is required to be carried together with the external computer. Use of the dedicated cable causes operability to deteriorate when the printer scans. When infrared radiation is used, an error frequently occurs in receiving or sending data because the effective angle of the directivity of an infrared ray is narrow and the effective communication distance is short.